PROJECT SUMMARY Increased attention is being paid to the need for a science of recruitment and retention in Alzheimer's disease clinical research. While barriers to successful and efficient recruitment are being elucidated, less work has focused on retaining longitudinal research participants. Poor retention stands to undue successful recruitment and can result in bias and scientific error. The purpose of this supplement application is to add the UC Irvine ADRC to a funded NACC Collaborative study to improve the retention of participants in longitudinal AD research studies. The objective of this study is to identify facilitators and barriers to longitudinal research participation and develop new guidelines to increase study retention. We will conduct a comprehensive survey of research participants age 45 years and older enrolled in our longitudinal cohort who have been noncompliant with their clinical visits using an AD research-specific survey; their study partners will also be surveyed. Findings will inform the development of guidelines that aim to improve retention in longitudinal AD studies.